CN110945082B - Heat conductive resin molded article - Google Patents
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- CN110945082B CN110945082B CN201880048210.4A CN201880048210A CN110945082B CN 110945082 B CN110945082 B CN 110945082B CN 201880048210 A CN201880048210 A CN 201880048210A CN 110945082 B CN110945082 B CN 110945082B
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/02—Physical, chemical or physicochemical properties
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- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
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- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
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- C08L101/00—Compositions of unspecified macromolecular compounds
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/24—Acids; Salts thereof
- C08K3/26—Carbonates; Bicarbonates
- C08K2003/267—Magnesium carbonate
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Abstract
A thermally conductive resin molded article comprising a resin and a thermally conductive filler, wherein the thermally conductive filler comprises a first thermally conductive filler and a second thermally conductive filler having a smaller particle diameter than the first thermally conductive filler, the thermally conductive resin molded article contains 30 to 50 vol% of the thermally conductive filler, the first thermally conductive filler contains boron nitride having a particle diameter of 30 [ mu ] m or more and an aspect ratio of 10 or more, the first thermally conductive filler contains 5 to 20 vol% of the thermally conductive filler, and the second thermally conductive filler contains a material other than boron nitride. The thermally conductive resin molded article of the present invention has excellent thermal conductivity.
Description
Technical Field
The present invention relates to a thermally conductive resin molded article.
Background
In recent years, electronic devices have been rapidly developed to have higher density and thinner profile, and the influence of heat generated from Integrated Circuits (ICs), power components, and high-brightness Light Emitting Diodes (LEDs) has become a significant problem. In order to solve the above problem, for example, a sheet (sheet) -shaped thermally conductive resin molded product is being used as a member for efficiently transferring heat between a heat generating body such as a chip and a radiator.
Here, as a method for imparting high thermal conductivity to a resin molded product, it is known that a thermal conductive filler is oriented and dispersed in a resin in order to efficiently form a thermal conduction path (path).
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. Hei 08-244094
Patent document 2: japanese patent application laid-open No. 2010-260225
Disclosure of Invention
Problems to be solved by the invention
The thermally conductive resin molded articles described in patent documents 1 and 2 preferably use a boron nitride filler as the thermally conductive filler. The boron nitride filler has an advantage that excellent thermal conductivity is easily imparted. However, boron nitride is expensive, and when a large amount of boron nitride filler is contained as in patent documents 1 and 2, it is difficult to provide a thermally conductive resin molded product at low cost.
On the other hand, in the case where only a filler made of boron nitride is used as the thermally conductive filler, if the content of the filler is small, it is difficult to orient the filler. As a result, there are problems as follows: the resulting resin molded article uses a filler made of boron nitride, but has poor thermal conductivity.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a thermally conductive resin molded article having excellent thermal conductivity and capable of being produced at low cost.
Means for solving the problems
(1) The thermally conductive resin molded product of the present invention comprises a resin and a thermally conductive filler, wherein the thermally conductive filler comprises a first thermally conductive filler and a second thermally conductive filler having a smaller particle diameter than the first thermally conductive filler,
the resin is a silicone rubber, and the resin is,
the content of the thermally conductive filler is 30 to 50 vol%,
the first thermally conductive filler is a filler containing boron nitride and having a particle diameter of 30 [ mu ] m or more and an aspect ratio of 10 or more,
the first thermally conductive filler is contained in an amount of 5 to 20 vol%
The second thermally conductive filler is a filler containing a material other than boron nitride.
The thermally conductive resin molded article of the present invention has an upper limit of the total content of the thermally conductive filler suppressed to 50 vol%, and contains a predetermined amount of a first thermally conductive filler containing boron nitride and a predetermined amount of a second thermally conductive filler containing a material other than boron nitride and having a smaller particle diameter than the first thermally conductive filler.
Therefore, according to the thermally conductive resin molded article, even if the content of the first thermally conductive filler containing boron nitride is small, the first thermally conductive filler can be oriented, and the thermally conductive resin molded article has excellent thermal conductivity.
Further, the thermally conductive resin molded article can be provided at low cost.
(2) In the thermally conductive resin molded product, the particle diameter of the second thermally conductive filler is preferably 3 to 20 μm.
In this case, the second thermally conductive filler is preferably interposed between the first thermally conductive fillers to improve the thermal conductivity of the thermally conductive resin molded product, and is also preferably oriented in the step of producing the thermally conductive resin molded product.
(3) In the thermally conductive resin molded product, the second thermally conductive filler preferably contains magnesium oxide or magnesium carbonate.
In this case, the second thermally conductive filler is preferably interposed between the first thermally conductive fillers to improve the thermal conductivity of the thermally conductive resin molded article, and is preferably used to provide the thermally conductive resin molded article at low cost.
ADVANTAGEOUS EFFECTS OF INVENTION
The thermally conductive resin molded article of the present invention has excellent thermal conductivity.
Further, the thermally conductive resin molded article can be provided at low cost.
Drawings
Fig. 1 is a cross-sectional view schematically showing a thermal conductive sheet according to an embodiment of the present invention.
Fig. 2 is a view schematically showing an extruder used for producing a thermal conductive sheet according to an embodiment of the present invention.
Description of the symbols
1: heat conductive sheet
2: matrix composition
4: first heat conductive filler
5: second thermally conductive filler
6: weld line
8: screw rod
10: flow path
12: first gap
14: second gap
100: extruding machine
Detailed Description
Embodiments of the present invention will be described below.
In the present invention, the term "thermally conductive resin molded article" is a concept including either a block obtained by molding a raw material composition or a cut-off material (including a sheet material obtained by slicing) obtained by cutting the block.
In this embodiment, an embodiment of the thermally conductive resin molded product will be described by taking a thermally conductive sheet as an example.
Fig. 1 is a cross-sectional view schematically showing a thermal conductive sheet according to an embodiment of the present invention, and is a cross-sectional view parallel to the thickness direction of the thermal conductive sheet. Further, fig. 1 is a schematic view, and the components (particularly, the first thermally conductive filler and the second thermally conductive filler) do not accurately reflect the actual dimensions.
The thermal conductive sheet 1 of the present embodiment is disposed between a heat generating member such as an IC chip and a heat dissipating member such as a heat sink (heat sink), and is used such that one surface thereof is in contact with the heat generating member and the other surface thereof is in contact with the heat dissipating member.
As shown in fig. 1, the thermal conductive sheet 1 includes a matrix component 2, and a first thermal conductive filler 4 and a second thermal conductive filler 5, and the first thermal conductive filler 4 is oriented substantially in the thickness direction (vertical direction in fig. 1) of the thermal conductive sheet 1. In the thermal conductive sheet 1, a thermal conduction path formed by the first thermal conductive filler 4 and the second thermal conductive filler 5 is formed substantially in the thickness direction of the thermal conductive sheet 1. Therefore, the thermal conductivity of the thermal conductive sheet 1 in the thickness direction is excellent.
In the thermally conductive sheet, components other than the thermally conductive filler are collectively referred to as matrix components.
The thermal conductive sheet 1 is obtained by slicing (slice) a block, which is formed by closely bonding thin resin sheets in which the first thermal conductive filler 4 in the matrix component 2 is dispersed in an orientation in the planar direction, in a state of being folded in the vertical direction. The heat conductive sheet 1 may have a weld line 6 formed substantially in the thickness direction.
The matrix component 2 contains at least a resin (including rubber).
The resin may be suitably selected from various conventionally known resins.
Specifically, for example, ethylene- α -olefin copolymers such as polyethylene, polypropylene and ethylene-propylene copolymers, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohol, polyacetal, fluorine-based resins such as polyvinylidene fluoride and polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyacrylonitrile, Styrene-Acrylonitrile copolymers, Acrylonitrile-Butadiene-Styrene (ABS) resins, polyphenylene oxide, modified polyphenylene oxide, aliphatic polyamides, aromatic polyamides, polyamideimides, polymethacrylic acid or esters thereof, polyacrylic acid or esters thereof, polycarbonate, polyphenylene sulfide, polysulfone, polyether sulfone, and the like, can be used, Polyether nitriles, polyether ketones, polyketones, liquid crystal polymers, silicone resins, ionomers, and the like.
Further, for example, styrene-based thermoplastic elastomers such as styrene-butadiene copolymers or hydrogenated polymers thereof, styrene-isoprene block copolymers or hydrogenated polymers thereof, olefin-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and the like can be used.
Further, for example, silicone rubber, acrylic rubber, butyl rubber, fluorine rubber, nitrile rubber, hydrogenated nitrile rubber, and the like can also be used.
These may be used alone, or 2 or more of them may be used in combination.
Among these, silicone rubber is preferable in terms of excellent flexibility and shape-following properties when formed into a molded article, adhesion to a heat-generating surface when contacting an electronic component, and heat resistance.
Examples of the silicone rubber include those obtained by crosslinking a polymer (silicone) having a silicone skeleton.
Here, the crosslinking of the silicone may be peroxide crosslinking or addition reaction type crosslinking, but peroxide crosslinking is preferable. Since the silicone rubber obtained by crosslinking by peroxide crosslinking is excellent in heat resistance.
The silicone rubber is preferably obtained by peroxide crosslinking a mixture of a silicone having all methyl groups in the side chains and containing no unsaturated groups and a silicone having vinyl groups in a part of the side chains (including the terminal ends).
In this case, the silicone having a vinyl group in a part of the side chain can also be considered as a crosslinking agent for a silicone having methyl groups in all the side chains and containing no unsaturated group.
Specific examples of the silicone having a vinyl group in a part of the side chain include: dimethyl vinyl siloxy blocked dimethyl polysiloxane at two ends of a molecular chain, methyl phenyl vinyl siloxy blocked dimethyl polysiloxane at two ends of a molecular chain, dimethyl vinyl siloxy blocked dimethyl siloxane-methyl phenyl siloxane copolymer at two ends of a molecular chain, dimethyl vinyl siloxy blocked dimethyl siloxane-methyl vinyl siloxane copolymer at two ends of a molecular chain, trimethylsiloxy-blocked dimethylsiloxane-methylvinylsiloxane copolymers at both ends of the molecular chain, dimethylvinylsiloxy-blocked methyl (3,3, 3-trifluoropropyl) polysiloxane at both ends of the molecular chain, silanol-blocked dimethylsiloxane-methylvinylsiloxane copolymers at both ends of the molecular chain, silanol-blocked dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers at both ends of the molecular chain, and the like. These may be used alone or in combination of two or more.
Examples of the organic peroxide used for the peroxide crosslinking include: benzoyl peroxide, dicumyl peroxide, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, di-t-butyl peroxide, t-butyl perbenzoate, and the like. These may be used alone or in combination of two or more.
Further, a crosslinking accelerator or a crosslinking accelerator aid may be used in combination at the time of crosslinking.
The matrix component 2 may contain a crosslinking agent, a crosslinking accelerator, and a crosslinking accelerator aid, as described above, in addition to the resin. The matrix component 2 may contain general additives such as reinforcing agents, fillers, softeners, plasticizers, antioxidants, adhesion imparting agents, antistatic agents, kneading adhesives, flame retardants, coupling agents, and the like.
The thermal conductive sheet 1 contains 2 kinds of thermal conductive fillers, i.e., a first thermal conductive filler 4 and a second thermal conductive filler 5 having a smaller particle size than the first thermal conductive filler 4.
First thermally conductive filler 4 contains Boron Nitride (BN). Therefore, the thermal conductive sheet 1 has excellent thermal conductivity.
The shape of first thermally conductive filler 4 is not particularly limited as long as it has a predetermined particle diameter and aspect ratio. Specific shapes of the first thermally conductive filler 4 include, for example: scale-like, plate-like, film-like, fibrous, cylindrical, prismatic, elliptical, flat, etc.
Among these shapes, a scale shape is preferable. The reason is that the molded article has a high aspect ratio and has isotropic thermal conductivity in the plane direction, and therefore, when the scale-like thermally conductive filler is oriented, the thermal conductivity of the molded article becomes high.
The particle diameter of first thermally conductive filler 4 is 30 μm or more. If the particle size is less than 30 μm, a heat conduction path may be difficult to form and the heat conductivity may be poor.
On the other hand, from the viewpoint of processability in producing a thermally conductive resin molded product, the preferable upper limit of the particle diameter of the first thermally conductive filler 4 is 100 μm.
The aspect ratio of first thermally conductive filler 4 is 10 or more. In this case, the second thermally conductive filler 5 having a smaller particle size than the first thermally conductive filler 4 is dispersed in the gaps of the first thermally conductive filler 4 and easily forms a thermal conduction path, and the first thermally conductive filler 4 is easily oriented in the matrix component 2.
On the other hand, the upper limit of the aspect ratio of the first thermally conductive filler 4 is preferably 100. In this case, the first thermally conductive filler is easily filled in the thermally conductive resin molded product, and the processability in producing the thermally conductive resin molded product is also excellent.
In the present invention, the "particle diameter" of the thermally conductive filler is a concept of an average particle diameter in the measurement of particle size distribution. The average particle diameter is measured by a laser diffraction scattering method (apparatus: Mack (Microtrac) MT3300EXII manufactured by Microtrac-Bel Ltd.).
In the present invention, the "aspect ratio" of the thermally conductive filler is an average value of the ratio of the major axis to the minor axis. The aspect ratio is obtained by arbitrarily selecting 200 or more particles from an image captured by a Scanning Electron Microscope (SEM), and calculating the ratio of the major axis to the minor axis of each particle to calculate the average value. Here, the major axis and the minor axis are defined such that, in an observation image of each particle, the length of the longest portion is defined as the major axis, and the length of a portion that passes through the midpoint of the major axis and is orthogonal to the major axis is defined as the minor axis.
The second thermally conductive filler 5 has a smaller particle diameter than the first thermally conductive filler and contains a material other than boron nitride.
The second thermally conductive filler 5 may be a material other than boron nitride and has thermal conductivity. Specific examples of the second thermally conductive filler 5 include fillers containing graphite, Carbon fiber, Carbon Nanotube (CNT), mica, alumina, aluminum nitride, silicon carbide, silica, zinc oxide, magnesium oxide, calcium carbonate, magnesium carbonate, molybdenum disulfide, copper, aluminum, and the like.
Of these, a thermally conductive filler containing magnesium oxide and a thermally conductive filler containing magnesium carbonate are preferable. This is because it is suitable for interposing the first thermally conductive fillers 4 between them to improve the thermal conductivity of the thermally conductive sheet 1, and is suitable for providing the thermally conductive sheet 1 at low cost.
The shape of second thermally conductive filler 5 is not particularly limited, and specific examples thereof include: spherical, scaly, plate-like, film-like, cylindrical, prismatic, elliptical, flat, etc.
The shape of the second thermally conductive filler 5 is preferably spherical or scaly. This is because, in this case, a heat conduction path is easily formed between the first thermally conductive fillers 4, and the first thermally conductive fillers 4 are preferably oriented.
The particle size of second thermally conductive filler 5 is not particularly limited as long as it is smaller than the particle size of first thermally conductive filler 4, but is preferably 3 to 20 μm.
If the particle diameter of second thermally conductive filler 5 is in the above range, it is more preferable to interpose first thermally conductive fillers 4 between each other and form a thermal conduction path, and to orient first thermally conductive fillers 4. Further, when the particle diameter of the second thermally conductive filler 5 is in the above range, it is preferable to suppress the surface roughness of the thermally conductive sheet 1 and reduce the contact thermal resistance when contacting the heat generating member or the heat radiating member (thermal resistance of the surface of the thermally conductive sheet 1).
On the other hand, if the particle diameter of the second thermally conductive filler 5 exceeds 20 μm, the first thermally conductive filler 4 becomes difficult to align, and the thermal conductivity of the thermally conductive sheet 1 may be poor.
When the particle diameter of the second thermally conductive filler 5 is less than 3 μm, the thermal conductivity of the thermally conductive sheet 1 may be poor depending on the material of the second thermally conductive filler 5. For example, when the material of the second thermally conductive filler 5 is magnesium oxide or magnesium carbonate, foaming of the second thermally conductive filler 5 may occur during the production of the thermally conductive sheet 1, and when such foaming occurs, the thermal conductivity of the produced thermally conductive sheet 1 may decrease.
The particle diameter of second thermally conductive filler 5 is more preferably 5 μm to 20 μm, still more preferably 5 μm to 15 μm, and particularly preferably 5 μm to 10 μm.
The upper limit of the aspect ratio of second thermally conductive filler 5 is preferably 100. The reason is that the second thermally conductive filler is easily filled in the thermally conductive resin molded product, and the workability in producing the thermally conductive resin molded product is also excellent.
The lower limit of the aspect ratio of second thermally conductive filler 5 is not limited, and the aspect ratio of second thermally conductive filler 5 may be 1 or more.
The method of measuring the particle diameter and the aspect ratio of the second thermally conductive filler 5 is the same as the method of measuring the particle diameter and the aspect ratio of the first thermally conductive filler 4.
The content of the thermally conductive filler (the total content of the thermally conductive filler) in the thermally conductive sheet 1 is 30 to 50 vol%.
If the total content of the thermally conductive filler is less than 30% by volume, sufficient thermal conductivity cannot be secured. When the content exceeds 50% by volume, the workability in producing a thermally conductive resin molded article is deteriorated, and it is difficult to provide a thermally conductive resin molded article at low cost.
The content of the first thermally conductive filler 4 in the thermally conductive sheet 1 is 5 to 20 vol%. In this case, the first thermally conductive filler can be oriented to ensure thermal conductivity.
On the other hand, if the content of the first thermally conductive filler 4 is less than 5 vol%, sufficient thermal conductivity cannot be secured even if the first thermally conductive filler is oriented. If the content exceeds 20 vol%, it is difficult to provide a thermally conductive resin molded article at low cost.
The content of the second thermally conductive filler 5 in the thermally conductive sheet 1 is preferably 10 to 45 vol%.
If the content of the second thermally conductive filler 5 is less than 10 vol%, it becomes difficult to orient the first thermally conductive filler during molding. On the other hand, if the content of the second thermally conductive filler 5 exceeds 45 vol%, the content of the first thermally conductive filler becomes too small, and sufficient thermal conductivity cannot be secured.
The content of second thermally conductive filler 5 is more preferably 20 to 45 vol%.
The thermal conductive sheet 1 of the present embodiment contains a first thermal conductive filler 4 and a second thermal conductive filler 5 as thermal conductive fillers. Here, the particle diameter D1 of the first thermally conductive filler 4 and the particle diameter D2 of the second thermally conductive filler 5 have a relationship of D1 > D2.
The thermal conductive sheet 1 may contain a thermal conductive filler other than the first thermal conductive filler 4 and the second thermal conductive filler 5 within a range not to impair the effects of the present invention.
The thickness of the thermal conductive sheet 1 is not particularly limited, and is, for example, about 0.1mm to 3.0 mm.
In this case, the thermal conductive sheet 1 can be suitably used as a member for efficiently transferring heat between a heat generating member and a heat dissipating member in an electric component, an automobile component, or the like.
Next, a method for manufacturing the thermal conductive sheet according to the present embodiment will be described with reference to the drawings.
Fig. 2 is a view schematically showing an extruder used for producing a thermal conductive sheet according to an embodiment of the present invention. Fig. 2 is a schematic sectional view of the tip portion of the extruder 100 and a T-die.
The raw material composition containing the thermally conductive filler charged into the extruder 100 is stirred and kneaded by the screw 8, and is introduced into the first gap (gap)12 along the flow path 10.
The raw material composition charged into the extruder 100 is first twisted in the vertical direction (thickness direction) through the first gap 12 to form a thin strip. When passing through the first gap 12, a shearing force acts on the raw material composition, and the first thermally conductive filler mixed in the raw material composition is oriented in the flow direction of the raw material composition. Therefore, in the resin sheet precursor formed with a thin thickness by the first gap 12, at least the first thermally conductive filler is oriented in the plane direction of the resin sheet precursor.
In addition, in the case where the second thermally conductive filler is a filler having an orientable shape, the second thermally conductive filler is oriented in the same direction as the first thermally conductive filler when passing through the first gap 12.
The gap (the vertical dimension in fig. 2) of the first gap 12 is preferably 0.1mm to 5.0 mm. If the gap of the first gap 12 is less than 0.1mm, the extrusion pressure may rise unnecessarily, and resin clogging may occur. On the other hand, if the gap of the first gap 12 is larger than 5.0mm, the degree of orientation of the thermally conductive filler with respect to the plane direction of the thin resin sheet precursor may decrease.
When the thin resin sheet precursor in which the first thermally conductive filler is oriented in the plane direction completely passes through the first gap 12, the flow direction of the sheet limited to the extrusion direction is released, and the flow direction changes to a direction substantially perpendicular to the extrusion direction. This is because the cross-sectional area of the flow channel 10 after passing through the first gap 12 is increased, and the length of the flow channel 10 in the vertical direction is increased.
The thin resin sheet precursor, in which the sheet flow direction is changed to a direction substantially perpendicular to the extrusion direction, is extruded toward the second gap 14 after completely passing through the first gap 12. As a result, the resin sheet precursor in the second gap 14 is in a state in which the thin resin sheet precursors are laminated. At this time, most of the first thermally conductive filler is oriented in the thickness direction (vertical direction in fig. 2) of the resin sheet precursor in the second gap 14.
Thereafter, the resin sheet precursor is heated under predetermined conditions as necessary to crosslink the resin sheet precursor, and the resin sheet precursor is further sliced in a direction perpendicular to the thickness direction as necessary. The thermal conductive sheet 1 is manufactured through such steps.
Here, the gap of the second gap 14 is preferably 2 times or more and 20 times or less the gap of the first gap 12. When the gap of the second gap 14 is smaller than 2 times the gap of the first gap 12, the first thermally conductive filler 4 may not be oriented in the thickness direction of the thermally conductive sheet 1. When the gap of the second gap 14 is larger than 20 times the gap of the first gap 12, local turbulence of the resin sheet precursor is likely to occur, and as a result, the proportion of the first thermally conductive filler 4 oriented in the thickness direction of the thermally conductive sheet 1 may decrease.
The gap of the second gap 14 is more preferably 2 times or more and 10 times or less the gap of the first gap 12.
In addition, from the viewpoint that the resin sheet precursor easily flows uniformly in the vertical direction of the flow path 10, it is preferable that the center in the thickness direction in the first gap 12 and the center in the thickness direction in the second gap 14 are at substantially the same position in the thickness direction.
The shape of the opening portion continuous with the first gap 12 is not particularly limited, but it is preferable that the side surface (upper and lower surfaces) of the opening portion on the upstream side is an inclined surface so as to reduce the pressure loss, and the side surface (upper and lower surfaces) of the opening portion on the downstream side is preferably adjusted in inclination angle (angle formed by the extrusion direction and the inclined surface) in order to efficiently orient the heat conductive filler in the thickness direction of the resin sheet. The inclination angle may be, for example, 10 ° to 50 °, and more preferably 20 ° to 25 °.
The opening portion connected to the first gap 12 does not need to be inclined vertically, and only one of the opening portions may be inclined.
The depth of the first gap 12 and the second gap 14 (i.e., the gap between the first gap 12 and the second gap 14 in the direction substantially perpendicular to the plane of the drawing in fig. 2) is substantially the same throughout the entire T-die. The depth of the first gap and the second gap is not particularly limited, and various design changes can be made according to the product width of the resin sheet.
The thermal conductive sheet according to the embodiment of the present invention can also be produced by the following production method.
Namely, it can be produced by the following method: after a raw material composition for producing a thermal conductive sheet is prepared, a plurality of sheets in which at least a first thermal conductive filler is oriented in the plane direction are produced using the raw material composition by a conventionally known method, the sheets are stacked to produce a block, and then the block (stacked body of sheets) is cut from a direction perpendicular to the direction in which the first thermal conductive filler is oriented. In the case of producing the thermal conductive sheet by the above method, the crosslinking treatment may be performed at an appropriate timing as necessary.
The thermal conductive sheet produced by such a method is also a sheet in which the first thermal conductive filler is oriented in the approximate thickness direction of the thermal conductive sheet and which has excellent thermal conductivity.
Examples
The present invention will be described in further detail with reference to examples, but the present invention is not limited to the examples.
(example 1)
A crosslinking agent and the first thermally conductive filler were kneaded with the second thermally conductive filler (hereinafter, all of them will be collectively referred to as raw material components) in the resin component by 2 rolls in the formulation described in table 1 to obtain a tape sheet (composition as a precursor).
As the resin component, silicone rubber "DY 321005U available from Toray Dow Corning (Toray Dow Corning)" and a plasticizer (silicone oil KF-96-3000CS available from shin-Etsu chemical Co., Ltd.) were used.
As the crosslinking agent, "MR-53" and "RC-450P FD" manufactured by Toray Dow Corning (Toray Dow Corning) Co., Ltd are used. The total content thereof is shown in table 1.
As the first thermally conductive filler, a filler containing boron nitride ("XGP" (scaly, particle diameter 35 μm, aspect ratio of about 30)) manufactured by dunca (Denka) gmbh was used.
The second thermally conductive filler used was a filler containing magnesium carbonate (cubic, 6 μm in particle diameter, and about 1 in aspect ratio (manufactured by shenisai chemical industries, ltd)).
Then, with respect to the produced strip-shaped sheet, a 10 mm-thick sheet in which the first thermally conductive filler (scaly boron nitride) was oriented in the thickness direction was produced using a vertical orientation die (die orifice) having a first gap of 1mm and a second gap of 10mm in a short-axis extruder 100 for rubber shown in fig. 2, and the sheet was subjected to a crosslinking treatment at 170 ℃ for 30 minutes. The sheet after the crosslinking treatment was sliced perpendicularly to the thickness direction to produce the thermal conductive sheet 1 as a thermal conductive resin molded article having a thickness of 500 μm.
(example 2)
A thermal conductive sheet 1 was produced in the same manner as in example 1, except that the blending amounts of the raw material components were changed as shown in table 1.
(example 3)
A thermal conductive sheet 1 was produced in the same manner as in example 1, except that a filler containing magnesium carbonate (cubic, 15 μm in particle size, and about 1 in aspect ratio (manufactured by shenisai chemical industries, ltd)) was used as the second thermal conductive filler, and the amounts of the raw material components were changed as shown in table 1.
(example 4)
A thermal conductive sheet 1 was produced in the same manner as in example 1, except that the blending amounts of the raw material components were changed as shown in table 1.
(example 5)
Thermal conductive sheet 1 was produced in the same manner as in example 1, except that a filler containing magnesium oxide ("SMO" (spherical, particle size 10 μm, and aspect ratio of about 1) made by sakai chemical industry ltd was used as the second thermal conductive filler, and the blending amounts of the raw material components were changed as shown in table 1.
(example 6)
A thermal conductive sheet 1 was produced in the same manner as in example 5, except that the blending amounts of the raw material components were changed as shown in table 1.
(example 7)
A thermal conductive sheet 1 was produced in the same manner as in example 1, except that a filler containing magnesium carbonate (cubic, 26 μm in particle size, and about 1 in aspect ratio (manufactured by shenisai chemical industries, ltd)) was used as the second thermal conductive filler, and the blending amounts of the raw material components were changed as shown in table 1.
(example 8)
A thermal conductive sheet 1 was produced in the same manner as in example 3, except that the blending amounts of the raw material components were changed as shown in table 1.
(example 9)
A thermal conductive sheet 1 was produced in the same manner as in example 1, except that the blending amounts of the raw material components were changed as shown in table 1.
(example 10)
A thermal conductive sheet 1 was produced in the same manner as in example 7, except that a filler containing calcium carbonate ("light calcium carbonate" (spherical, particle size 6 μm, aspect ratio of about 1)) was used as the second thermal conductive filler.
(example 11)
A thermal conductive sheet 1 was produced in the same manner as in example 7, except that a filler containing magnesium oxide ("starmar MSL" (spherical, particle size of 9 μm, aspect ratio 1)) was used as the second thermal conductive filler.
Comparative examples 1 and 2
A thermal conductive sheet 1 was produced in the same manner as in example 1, except that the blending amounts of the raw material components were changed as shown in table 1 (the second thermal conductive filler was not used).
[ evaluation test ]
(1) Hardness of
As the hardness of the obtained thermally conductive resin sheet, an Asker (Asker) C hardness was measured. The results are shown in Table 1.
(2) Thermal resistance
The thermal resistance in the thickness direction of the obtained thermally conductive resin sheet was measured using a tim tester (TIM TESTER)1300 at measurement pressures of 3 levels (0.1MPa, 0.3MPa, and 0.5 MPa). The values obtained by the measurement are shown in table 1. Again, the measurements were made by the steady state method and according to the American Society for Testing and Materials (ASTM) D5470. The results are shown in Table 1.
[ Table 1]
As is clear from the results shown in table 1, according to the embodiment of the present invention, a thermally conductive resin sheet with a low thermal resistance value can be provided while reducing the amount of expensive BN used.
Claims (2)
1. A thermally conductive resin molded article comprising a resin and a thermally conductive filler, the thermally conductive filler comprising a first thermally conductive filler and a second thermally conductive filler having a smaller particle diameter than the first thermally conductive filler,
the resin is a silicone rubber, and the resin is,
the content of the thermally conductive filler is 30 to 50 vol%,
the first thermally conductive filler is a filler containing boron nitride and having a particle diameter of 30 [ mu ] m or more and an aspect ratio of 10 or more,
the first thermally conductive filler is contained in an amount of 5 to 20 vol%
The second thermally conductive filler is a filler containing a material other than boron nitride,
the particle diameter of the second heat conductive filler is 3 to 20 μm,
the second thermally conductive filler is contained in an amount of 10 to 45 vol%.
2. The thermally conductive resin molded article according to claim 1, wherein the second thermally conductive filler is a filler containing magnesium oxide or magnesium carbonate.
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| JP2017148266 | 2017-07-31 | ||
| JP2017-148266 | 2017-07-31 | ||
| PCT/JP2018/028025 WO2019026745A1 (en) | 2017-07-31 | 2018-07-26 | Thermally conductive resin molded article |
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| JPH09296114A (en) * | 1996-04-30 | 1997-11-18 | Denki Kagaku Kogyo Kk | Silicone rubber composition and its use |
| CN103333494A (en) * | 2013-05-28 | 2013-10-02 | 东莞上海大学纳米技术研究院 | Thermal-conductive insulation silicone rubber thermal interface material and preparation method thereof |
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| JPH07157664A (en) * | 1993-12-03 | 1995-06-20 | Fuji Kobunshi Kogyo Kk | Thermally conductive silicone rubber sheet and its production |
| JP3698451B2 (en) | 1995-03-13 | 2005-09-21 | 電気化学工業株式会社 | Sheet manufacturing method |
| JP5405890B2 (en) | 2009-05-01 | 2014-02-05 | 電気化学工業株式会社 | Thermally conductive moldings and their applications |
| JP5312437B2 (en) * | 2010-12-07 | 2013-10-09 | 三菱エンジニアリングプラスチックス株式会社 | Thermally conductive polycarbonate resin composition and molded body |
| JP2012144626A (en) * | 2011-01-11 | 2012-08-02 | Daicel Corp | Thermally conductive resin composition and thermally conductive sheet |
| JP5678789B2 (en) * | 2011-04-26 | 2015-03-04 | 三菱エンジニアリングプラスチックス株式会社 | Thermally conductive polyalkylene terephthalate resin composition and molded body |
| JP2012229317A (en) * | 2011-04-26 | 2012-11-22 | Nitto Denko Corp | Transparent thermoconductive composition |
| CN102816438A (en) | 2011-06-06 | 2012-12-12 | 日东电工株式会社 | Silicone resin composition and thermal conductive sheet |
| JP6161875B2 (en) * | 2011-09-14 | 2017-07-12 | 株式会社日本触媒 | Thermally conductive material |
| JP2013127035A (en) * | 2011-12-19 | 2013-06-27 | Two-One:Kk | Thermal conductivity rubber composition that excels in insulation, flame retardancy, mechanical property, and flexibility, and where circuit contact failure is not caused, molding and sheet comprising the rubber composition, and manufacturing method of the same |
| JP6375140B2 (en) * | 2014-04-30 | 2018-08-15 | 日東電工株式会社 | Thermally conductive polymer composition and thermally conductive molded body |
| JP6988091B2 (en) * | 2014-12-08 | 2022-01-05 | 昭和電工マテリアルズ株式会社 | Epoxy resin composition, resin sheet, prepreg, metal foil with resin, metal substrate, and power semiconductor device |
| JP6200119B1 (en) * | 2016-02-01 | 2017-09-20 | バンドー化学株式会社 | Thermally conductive resin molded product |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09296114A (en) * | 1996-04-30 | 1997-11-18 | Denki Kagaku Kogyo Kk | Silicone rubber composition and its use |
| CN103333494A (en) * | 2013-05-28 | 2013-10-02 | 东莞上海大学纳米技术研究院 | Thermal-conductive insulation silicone rubber thermal interface material and preparation method thereof |
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| DE112018003897T5 (en) | 2020-04-16 |
| CN110945082A (en) | 2020-03-31 |
| JP6490877B1 (en) | 2019-03-27 |
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| TW201910131A (en) | 2019-03-16 |
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